In a commonly used inkjet printer, heat applied to ink stored in its head produces bubbles like soap bubbles. The bubbles are ejected through nozzles to form characters on a sheet of printing paper. In this method fonts or figures are represented onto sheets of paper. This mode is also called ink bubble jet because it uses bubbles.
Such a printer usually uses about 64 nozzles. Its form of font can be downloaded by a program, and photographs or figures can be also printed. The resolution of fonts or figures in the inkjet printer is generally 360 DPI (dot per inch). Depending upon the kind of head installed, color printing is available.
A general construction of the inkjet printer has a carrier supported on a main frame and moving left and right by a time belt along a belt pulley, a head mounted on the carrier and moving therewith for ejecting ink, nozzles installed in the head and through which ink is ejected in a predetermined form, a plate rotatably installed on the main frame for carrying paper and simultaneously supporting it during printing, a pressing board fixed to the main frame for making the paper tightly contact the plate, and a wiper/cap for washing or closing the nozzles according to a cleaning signal in a predetermined interval during printing. This kind of conventional inkjet printer is explained below with reference to the attached drawings.
Referring to FIG. 1 schematically showing the inkjet printer, there are included a paper feeding portion or section 2 where paper sheets 1 are stored, a feeding roller 3 for supplying paper sheets 1 stored in paper feeding portion or section 2 for printing, a carrier 4 reciprocating to print on paper sheets 1 supplied by feeding roller 3, a shaft 5 for guiding the reciprocation of carrier 4, a head 6 guided by shaft 5 and mounted on reciprocating carrier 4 for ejecting ink with heat applied, an ink absorbing sponge 7 for cleaning the back side of the paper sheet not printed after its front side is printed with the ink ejected from head 6, and a conveying roller 8 for discharging paper sheet 1 passing through ink absorbing sponge 7. The operation of the above constructed inkjet printer is described below.
First of all, in order to output contents handled by a user via a personal computer (PC) (not shown) using the inkjet printer, paper sheets 1 are stored in paper feeding portion 2 of the inkjet printer. After the storage of paper, the user applies a printing command to the printer via the PC. Receiving the command, the inkjet printer rotates feeding roller 3 counterclockwise so that the leading end la of paper is carried to the bottom of nozzles of head 3.
Ink bubbles ejected from head 6 mounted on carrier 4 reciprocating along shaft 5 are attached to printing paper sheet 1 conveyed. Printing is performed by attaching the ink bubbles onto printing paper 1. Here, in order to prevent the lower portion of the inkjet printer from being contaminated when printing is carried out on an area surpassing the width of printing paper 1, rapidly drying ink is used. In an inkjet printer using such ink, the contamination source for the printer's backside is hard to fully eliminate because the ink is not removed.
For this reason, ink absorbing sponge 7 is mounted to remove the contamination caused due to printing exceeding the paper width. This ink absorbing sponge 7 absorbs and cleans ink surpassing the width of paper 1. Paper 1 completing the printing through the procedure comes out through feeding roller 8 in the direction of the arrow indicated in FIG. 1.
However, the ink absorbing sponge has a limited amount of absorption, and the material is for special use, increasing the production cost of the printer. In addition, printing beyond the width of paper unnecessarily consumes a great amount of ink.